Chemical mechanical polishing, also known as chemical mechanical planarization (referred to herein collectively as “CMP”), is a technique that has been conventionally used for the planarization of semiconductor wafers. CMP also is often used in the formation of microelectronic devices to provide a substantially smooth, planar surface suitable for subsequent fabrication processes such as photoresist coating and pattern definition. A typical CMP apparatus suitable for planarizing a semiconductor surface generally includes a wafer carrier configured to support, guide, and apply pressure to a wafer during the polishing process, a polishing compound such as a slurry to assist in the removal of material from the surface of the wafer, and a polishing surface such as a polishing pad. In addition, the polishing apparatus may include an integrated wafer cleaning system and/or an automated load/unload station to facilitate automatic processing of the wafers.
A wafer surface is generally polished by moving the surface of the wafer to be polished relative to the polishing surface in the presence of the slurry. In particular, the wafer is placed in the carrier such that the surface to be polished is placed in contact with the polishing surface, and the polishing surface and/or the wafer are moved relative to each other while slurry is supplied to the polishing surface. As a wafer is polished, the slurry and abraded materials from the wafer tend to glaze the polishing surface, making the polishing surface slick and reducing the polishing rate and efficiency.
One method of countering the glazing or smoothing of the polishing surface and achieving and maintaining high and stable polishing rates is to condition the polishing surface by removing old slurry particles and abraded particles which develop on the surface. Scraping the polishing surface with a sharp objector or roughening the polishing pad with an abrasive material restores the polishing surface, thus increasing the ability of the polishing surface to absorb slurry and increasing the polishing rate and efficiency of the polishing system.
One type of conventional conditioning apparatus and conditioning method utilizes an abrasive conditioning surface, such as a diamond-pointed disk or block, disposed on an end effector that is urged against the polishing surface as relative movement between the end effector and the polishing surface is effected. However, these conventional conditioning apparatuses and methods have proven undesirable for a variety of reasons. Typically, a conventional conditioning process is conducted for a predetermined period of time, regardless of the state of wear of the conditioning surface. Accordingly, if conditioning is performed with a worn conditioning surface, the efficiency and effectiveness of the conditioning process may be compromised. Further, conventional conditioning processes typically are conducted for a predetermined period of time regardless of the extent of conditioning of the polishing surface. In this regard, the life of the conditioning surface may be shortened by use during unnecessary conditioning of a polishing surface that has already achieved optimum conditioning. Moreover, conventional conditioning processes are not designed to monitor and account for the wearing of the conditioning surface or the extent of conditioning of the polishing surface in-situ, that is, during a conditioning process. Thus, uniform conditioning may not be achieved during a conditioning process or from process to process.
Accordingly, it is desirable to provide conditioning apparatuses that are configured for uniform in-situ conditioning and for uniform conditioning from polishing surface to polishing surface. In addition, it is desirable to provide conditioning methods that provide uniform in-situ conditioning and uniform conditioning from polishing surface to polishing surface. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.